Conductive Sheet, Touch Sensor, and Method for Manufacturing Touch Sensor

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a U.S. National stage of International Application No. PCT/JP2021/015625, filed on Apr. 15, 2021. This application claims priority to Japanese Patent Application No. 2020-089388 filed on May 22, 2020 with Japan Patent Office. The entire disclosure of Japanese Patent Application No. 2020-089388 is hereby incorporated herein by reference.

BACKGROUND

Field of the Invention

The present disclosure relates to a conductive sheet, a touch sensor, and a method for manufacturing a touch sensor and particularly relates to a conductive sheet that includes thin metal wires in a mesh shape, a touch sensor, and a method for manufacturing a touch sensor.

Background Information

Conventionally, electrodes used for a touch sensor include a thin metal wire pattern in a mesh shape formed on a transparent substrate. A typically used shape of mesh is a lattice shape in which polygons such as squares, rhombuses, or hexagons are densely laid. Unfortunately, such a lattice shape may cause interference with a periodic pattern of a black matrix of a display device disposed below the touch sensor to produce a moire (striped pattern).

A conductive mesh described in JP 2014-203664 A (Patent Document 1) has an irregular mesh pattern and causes the moire due to interference with the black matrix of the display device to be less likely to be produced.

SUMMARY

When the shape of mesh is in an irregular pattern to reduce moire, a narrower inner angle formed by intersection of a thin metal wire may increase a width of the thin metal wire near an intersection point, which may be visually recognized as glare. In addition, in a case of the irregular pattern, dense and sparse areas of the thin metal wires are generated in the same plane, which may be visually recognized as glare.

An object of the present disclosure is to provide a conductive sheet, a touch sensor, and a method for manufacturing a touch sensor that provide reduced glare and improved visibility in a case where the shape of mesh is in an irregular pattern.

To achieve the object described above, the first aspect of the present disclosure is a conductive sheet that includes a transparent substrate and a plurality of thin metal wires formed in a mesh shape on one surface of the transparent substrate. The plurality of thin metal wires includes an n-sided polygon (n≥5) formed in a virtual pattern and an inverted virtual pattern having a regular hexagon and virtually and densely laid on the transparent substrate and six connecting lines connecting the n-sided polygon and first to sixth intersection points disposed on respective sides of the virtual pattern. The virtual pattern has vertexes as first to sixth vertexes in a counterclockwise direction, an intersection point disposed on a side connecting the first vertex and the second vertex is the first intersection point, intersection points disposed on the respective sides of the virtual pattern are the second to sixth intersection points in the counterclockwise direction, and the first to sixth intersection points are disposed such that distances from the first vertex to the first intersection point, from the first vertex to the sixth intersection point, from the second vertex to the second intersection point, from the fourth vertex to the third intersection point, from the fourth vertex to the fourth intersection point, and from the sixth vertex to the fifth intersection point are equal. The inverted virtual pattern obtained by flipping the virtual pattern horizontally has vertexes as first to sixth vertexes in a clockwise direction, an intersection point disposed on a side connecting the first vertex and the second vertex is a first intersection point, intersection points disposed on the respective sides of the inverted virtual pattern are the second to sixth intersection points in the clockwise direction, and the first to sixth intersection points are disposed such that distances from the first vertex to the first intersection point, from the first vertex to the sixth intersection point, from the second vertex to the second intersection point, from the fourth vertex to the third intersection point, from the fourth vertex to the fourth intersection point, and from the sixth vertex to the fifth intersection point are equal. The virtual pattern and the inverted virtual pattern are densely laid such that the intersection points of adjacent virtual patterns or the inverted virtual pattern are overlapped with each other and that opening regions formed by the plurality of thin metal wires are aperiodically arranged. Relationships 150 μm to 3000 μm, A/4≤B≤3A/4, and 90°≤0 are established, where A is a length of one side of the virtual pattern, B is a length of one side of the n-sided polygon, and θ is an inner angle of the n-sided polygon, and

(i) the n-sided polygon satisfies n=5, five connecting lines of the connecting lines each connect a vertex of the n-sided polygon and an intersection point whose distance from the vertex is shortest, one connecting line connects a side of the n-sided polygon and the intersection point, and a relationship A/4≤C≤A/2 is established, where C is a length of the connecting line, or (ii) the n-sided polygon satisfies n≥6, the connecting lines each connect the vertex of the n-sided polygon and the intersection point whose distance from the vertex is shortest.

The second aspect of the present disclosure is the conductive sheet in the first aspect in which the n-sided polygon satisfies n≥6, and a relationship A/4≤C≤A/2 is established, where C is the length of the connecting line.

Such a configuration widens the inner angle formed by intersection of the thin metal wire and thus can prevent the width of the thin metal wire near the intersection point from getting thicker. In addition, the virtual patterns in which the n-sided polygon and the lines are evenly disposed are densely laid to form the thin metal wires, and thus the thin metal wires are evenly disposed. This can reduce glare and improve visibility.

The third aspect of the present disclosure is the conductive sheet in the first or second aspect in which the plurality of thin metal wires includes a first blackened layer, a metal layer, and a second blackened layer layered in this order from a side of the transparent substrate.

The fourth aspect of the present disclosure is the conductive sheet in the third aspect in which the plurality of thin metal wires includes a blackened layer formed on a side surface.

Such a configuration forms the blackened layer on the surface of the thin metal wires and thus can reduce reflectivity on the surface of the thin metal wires.

The fifth aspect of the present disclosure is a touch sensor that includes the conductive sheet of the first aspect including a plurality of electrodes formed by the plurality of thin metal wires and connection portions each formed at an end portion of the plurality of electrodes, terminal portions connected to external wiring lines, and routed wiring lines connecting the connection portions and the terminal portions.

Such a configuration can reduce glare of the thin metal wires and thus achieve the touch sensor that provides the improved visibility.

The sixth aspect of the present disclosure is the touch sensor in the fifth aspect in which the plurality of electrodes is formed in an operation region, the routed wiring lines are formed in a peripheral region other than the operation region, and dummy portions not electrically connected to the plurality of electrodes are further provided in a region of the operation region in which the plurality of electrodes is not formed.

The seventh aspect of the present disclosure is the touch sensor in the sixth aspect in which the plurality of electrodes has a band shape, and the plurality of electrodes and the dummy portions are alternately disposed.

Such a configuration forms the electrodes and dummy portions in the operation region, thus can reduce an electrode-visible phenomenon where the shape of the electrode pattern is observed by an operator, and achieve the touch sensor that provides the improved visibility.

The eighth aspect of the present disclosure is the touch sensor in the seventh aspect in which the dummy portions are made up of the plurality of thin metal wires.

Such a configuration makes up the electrodes and the dummy portions of the same thin metal wires to have the same pattern and thus can further improve the visibility.

The ninth aspect of the present disclosure is a method for manufacturing a touch sensor including sequentially forming a first blackened film layer, a metal film layer, and a second blackened film layer on one surface of a transparent substrate and simultaneously forming, by etching the first blackened film layer, the metal film layer, and the second blackened film layer, a plurality of electrodes formed of a plurality of thin metal wires, connection portions each formed at an end portion of the plurality of electrodes, terminal portions connected to external wiring lines, and routed wiring lines connecting the connection portions and the terminal portions. The plurality of thin metal wires includes an n-sided polygon (n≥5) formed in a virtual pattern and an inverted virtual pattern having a regular hexagon and virtually and densely laid on the transparent substrate and six connecting lines connecting the n-sided polygon and first to sixth intersection points disposed on respective sides of the virtual pattern and is formed such that the virtual pattern has vertexes as first to sixth vertexes in a counterclockwise direction, an intersection point disposed on a side connecting the first vertex and the second vertex is the first intersection point, intersection points disposed on the respective sides of the virtual pattern are the second to sixth intersection points in the counterclockwise direction, and the first to sixth intersection points are disposed such that distances from the first vertex to the first intersection point, from the first vertex to the sixth intersection point, from the second vertex to the second intersection point, from the fourth vertex to the third intersection point, from the fourth vertex to the fourth intersection point, and from the sixth vertex to the fifth intersection point are equal, the inverted virtual pattern obtained by flipping the virtual pattern horizontally has vertexes as first to sixth vertexes in a clockwise direction, an intersection point disposed on a side connecting the first vertex and the second vertex is the first intersection point, intersection points disposed on the respective sides of the inverted virtual pattern are the second to sixth intersection points in the clockwise direction, and the first to sixth intersection points are disposed such that distances from the first vertex to the first intersection point, from the first vertex to the sixth intersection point, from the second vertex to the second intersection point, from the fourth vertex to the third intersection point, from the fourth vertex to the fourth intersection point, and from the sixth vertex to the fifth intersection point are equal, that the virtual pattern and the inverted virtual pattern are densely laid such that the intersection points of adjacent virtual patterns or the inverted virtual pattern are overlapped with each other and that opening regions formed by the plurality of thin metal wires are aperiodically arranged, relationships 150 μm to 3000 μm, A/4≤B≤3A/4, and 90°≤θ are established, where A is a length of one side of the virtual pattern, B is a length of one side of the n-sided polygon is B, and θ is an inner angle of the n-sided polygon, and

(i) the n-sided polygon satisfies n=5, five connecting lines of the connecting lines each connect a vertex of the n-sided polygon and an intersection point whose distance from the vertex is shortest, one connecting line connects a side of the n-sided polygon and the intersection point, and a relationship A/4≤C≤A/2 is established, where C is a length of the connecting line, or (ii) the n-sided polygon satisfies n≥6, the connecting lines each connect the vertex of the n-sided polygon and the intersection point whose distance from the vertex is shortest.

Such a configuration simultaneously forms the plurality of electrodes, the connection portions, the terminal portions, and the routed wiring lines and thus can reduce the number of processes and time required for manufacturing.

The present disclosure can provide a conductive sheet, a touch sensor, and a method for manufacturing a touch sensor that provide reduced glare and improved visibility in a case where the shape of mesh is in an irregular pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 A, 1 B, and 1 C are respectively a schematic cross-sectional view, a schematic plan view of a conductive sheet 10 according to a first embodiment of the present disclosure, and a partially enlarged cross-sectional view of a thin metal wire 12 .

FIGS. 2 A and 2 B are respectively a partially enlarged plan view of a virtual pattern Xa and a partially enlarged plan view of an inverted virtual pattern Xb according to the first embodiment of the present disclosure.

FIG. 3 is a partially enlarged plan view illustrating how to densely lay the virtual pattern Xa and the inverted virtual pattern Xb.

FIGS. 4 A and 4 B are respectively a schematic plan view of a touch sensor according to a second embodiment of the present disclosure and a partially enlarged plan view of a region K of FIG. 4 A .

DETAILED DESCRIPTION OF EMBODIMENTS

Next, a first embodiment of the present disclosure will be described with reference to the drawings.

First Embodiment

Referring to FIG. 1 A , the conductive sheet 10 according to the first embodiment of the present disclosure includes a transparent substrate 11 and a plurality of thin metal wires 12 formed in a mesh shape on one surface of the transparent substrate 11 . Referring to FIG. 1 B , the plurality of thin metal wires 12 include a hexagon and six connecting lines that are formed in the virtual pattern Xa and the inverted virtual pattern Xb. The virtual pattern Xa in which a hexagon and six connecting lines are formed by the plurality of thin metal wires 12 and the inverted virtual pattern Xb obtained by flipping the Xa horizontally are densely laid such that intersection points disposed on the respective sides of adjacent virtual patterns Xa or the inverted virtual pattern Xb are overlapped with each other and that opening regions R formed by the plurality of thin metal wires 12 are aperiodically arranged. The detail of the virtual pattern Xa and the inverted virtual pattern Xb will be described below. Referring to FIG. 1 C , the thin metal wire 12 includes a first blackened layer 13 , a metal layer 14 , and a second blackened layer 15 layered from the transparent substrate 11 side. The first blackened layer 13 and the second blackened layer 15 are layers for reducing reflectivity of the thin metal wire 12 and thereby improving visibility.

The material of the transparent substrate 11 only needs to be flexible, is not limited to particular materials, and can use, for example, polyesters such as polyethylene terephthalate (PET), polylactic acid (PLA), and polyethylene naphthalate (PEN), polyolefins such as polyethylene (PE), polypropylene (PP), polystyrene, EVA, cycloolefin polymer (COP), and cyclic olefin copolymer (COC), resin film such as vinyl resin, polycarbonate (PC), polyamide, polyimide (PI), acrylic resin (PMMA), triacetyl cellulose (TAC), polyurethane, silicone, polyvinyl chloride, and polyvinyl fluoride. The thickness of the transparent substrate 11 is 5 to 500 μm, and is preferably 20 to 100 μm.

The transparent substrate 11 may be a film of a single layer or a film obtained by layering a plurality of layers. The transparent substrate 11 may include a phase difference film in the composition.

The material of the metal layer 14 is not limited to particular materials and can use, for example, gold, silver, copper, iron, nickel, chromium, aluminum, molybdenum, titanium, or an alloy thereof. A metallic oxide or metallic nitride of copper, nickel, chromium, aluminum, molybdenum, titanium or the like can be used as a material of the first blackened layer 13 and the second blackened layer 15 .

The wire width of the thin metal wire 12 is, for example, 1 to 10 μm, and is preferably from 1 to 5 μm. The thickness of the thin metal wire 12 is, for example, 120 nm to 1.2 μm. The film thickness of the first blackened layer and the second blackened layer is, for example, 10 to 100 nm, and the film thickness of the metal layer 14 is, for example, 100 nm to 1 μm. The opening ratio of the thin metal wire 12 is, for example, 95% or more, and is preferably 98% or more.

The detail of the virtual pattern Xa and the inverted virtual pattern Xb will be described below.

Referring to FIG. 2 A , the virtual pattern Xa is a regular hexagonal pattern that is drawn in a virtual manner on the transparent substrate 11 . The vertexes of the virtual pattern Xa are a first vertex P 1 a to a sixth vertex P 6 a in a counterclockwise direction. The intersection point disposed on the side connecting the first vertex P 1 a and the second vertex P 2 a is a first intersection point Q 1 a , and the intersection points disposed on the respective sides of the virtual pattern Xa are a second intersection point Q 2 a to a sixth intersection point Q 6 a . The first intersection point Q 1 a to the sixth intersection point Q 6 a are disposed on the respective sides of the virtual pattern Xa such that the distances between P 1 a and Q 1 a , between P 1 a and Q 6 a , between P 2 a and Q 2 a , between P 4 a and Q 3 a , between P 4 a and Q 4 a , and between P 6 a and Q 5 a are equal. Virtual arrows d 1 a to d 6 a are respectively drawn below vertexes of the first vertex P 1 a to the sixth vertex P 6 a . For the directions indicated by the virtual arrows d 1 a to d 6 a , when P 1 a is on the upper side and P 4 a is on the lower side as a line connecting P 1 a and P 4 a defined as the axis, d 1 a indicates the right direction, d 2 a indicates the right obliquely upward direction, d 3 a indicates the right obliquely downward direction, d 4 a indicates the right direction, d 5 a indicates the left obliquely downward direction, and d 6 a indicates the left obliquely upward direction. Note that, when the virtual pattern Xa is rotated clockwise by 60°, P 2 a is arranged at the position of P 1 a in FIG. 2 A . In the Xa rotated by 60°, when P 2 a is on the upper side and P 5 a is on the lower side as a line connecting P 2 a and P 5 a is defined as the axis, d 2 a indicates the right direction, d 3 a indicates the left obliquely downward direction, d 4 a indicates the right obliquely downward direction, d 5 a indicates the left direction, d 6 a indicates the right obliquely upward direction, and d 1 a indicates the right obliquely downward direction.

A hexagon Sa and connecting lines L 1 a to L 6 a are formed by the thin metal wires 12 in the virtual pattern Xa. The vertexes of the hexagon Sa and the first intersection point Q 1 a to the sixth intersection point Q 6 a are respectively connected by the connecting lines L 1 a to L 6 a . The hexagon Sa is disposed near the center of the virtual pattern Xa, and the connecting lines L 1 a to L 6 a radially extend from vertexes of the hexagon Sa to respective intersection points on sides of the virtual pattern Xa. Each of the connecting lines L 1 a to L 6 a connects the vertex of the hexagon Sa and either one of the intersection points Q 1 a to Q 6 a whose distance from the vertex is shortest.

Referring to FIG. 2 B , the inverted virtual pattern Xb is obtained by flipping the virtual pattern Xa horizontally. The vertexes of the inverted virtual pattern Xb are a first vertex P 1 b to a sixth vertex P 6 b in a clockwise direction. The intersection point disposed on the side connecting the first vertex P 1 b and the second vertex P 2 b is a first intersection point Q 1 b , and the intersection points disposed on the respective sides of the inverted virtual pattern Xb are a second intersection point Q 2 b to a sixth intersection point Q 6 b . The first intersection point Q 1 b to the sixth intersection point Q 6 b are disposed on the respective sides of the inverted virtual pattern Xb such that the distances between P 1 b and Q 1 b , between P 1 b and Q 6 b , between P 2 b and Q 2 b , between P 4 b and Q 3 b , between P 4 b and Q 4 b , and between P 6 b and Q 5 b are equal. Virtual arrows d 1 b to d 6 b are respectively drawn below the vertexes of the first vertex P 1 b to the sixth vertex P 6 b . For the directions indicated by the virtual arrows d 1 b to d 6 b , when P 1 b is on the upper side and P 4 b is on the lower side as a line connecting P 1 b and P 4 b defined as the axis, d 1 b indicates the left direction, d 2 b indicates the left obliquely upward direction, d 3 b indicates the left obliquely downward direction, d 4 b indicates the left direction, d 5 b indicates the right obliquely downward direction, and d 6 b indicates the right obliquely upward direction.

The virtual pattern Xa and the inverted virtual pattern Xb are densely laid such that a number of opening regions formed by the plurality of thin metal wires 12 are aperiodically arranged. In other words, the virtual pattern Xa and the inverted virtual pattern Xb are densely laid such that the opening regions having the same shape are not periodically arranged.

A method for densely laying the virtual patterns such that a number of opening regions are aperiodically arranged will be described.

The virtual patterns rotated clockwise by 60° are densely laid in combination. In other words, the virtual patterns to be used are a total of twelve types of the Xa, the Xa rotated by 60°, the Xa rotated by 120°, the Xa rotated by 180°, the virtual pattern Xa rotated by 240°, the Xa rotated by 300°, the Xb, the inverted Xb rotated by 60°, the Xb rotated by 120°, the Xb rotated by 180°, the Xb rotated by 240° and the Xb rotated by 300°.

The above-mentioned twelve types of virtual patterns and inverted virtual patterns are densely laid without any gaps on the transparent substrate 11 in accordance with two rules.

First, the virtual patterns and the inverted virtual patterns are densely laid such that any one of the intersection points of the virtual pattern or the inverted virtual pattern is overlapped with any one of the intersection points of adjacent virtual pattern or the inverted virtual pattern. Thus, the connecting line of the virtual pattern or the inverted virtual pattern is always connected to the connecting line of adjacent virtual pattern or the inverted virtual pattern. As a result, a number of the opening regions R by the plurality of thin metal wires are arranged. The opening region R is a polygonal shape formed in the virtual pattern or the inverted virtual pattern, or a region surrounded by the connecting lines and the sides of the polygonal shape.

Second, the virtual patterns and the inverted virtual patterns are densely laid such that the virtual arrows drawn below the opposed vertexes of the two virtual patterns or the two inverted virtual patterns located opposed via one side of the virtual patterns or the inverted virtual patterns face in the same direction, Thus, a number of the opening regions formed by the thin metal wires 12 can be aperiodically arranged.

Referring to FIG. 3 , an example of the method for densely laying the virtual patterns will be described.

A virtual pattern X 1 is the virtual pattern Xa in FIG. 2 A , a virtual pattern X 2 is obtained by rotating the inverted virtual pattern Xb in FIG. 2 B clockwise by 240°, and a virtual pattern X 3 is obtained by rotating the Xa clockwise by 240°. The X 1 and X 2 are located adjacent such that the side P 3 a -P 4 a of the X 1 and the side P 3 b -P 4 b of the X 2 are overlapped. In other words, the X 1 and X 2 share the side P 1 a -P 4 a of the X 1 (or the side P 3 b -P 4 b of the X 2 ). The X 2 and X 3 are located adjacent such that the side P 5 b -P 6 b of the X 2 and the side P 5 a -P 6 a of the X 3 are overlapped. In other words, the x 2 and X 3 share the side P 5 b -P 6 b of the X 2 (or the side P 5 a -P 6 a of the X 3 ). The X 1 and X 3 are located opposed to each other via the side P 4 b -P 5 b of the X 2 . The X 1 and X 3 are disposed such that the vertex P 4 a of the X 1 and the vertex P 5 a of the X 3 are located opposed to each other.

First, since the side P 3 a -P 4 a of the X 1 and the side P 3 b -P 4 b of the X 2 are located adjacent to each other in an overlapping manner, the intersection point Q 3 a of the X 1 and the intersection point Q 3 b of the X 2 are overlapped with each other. Thus, a connecting line L 3 a of the X 1 and a connecting line L 3 b of the X 2 are connected. Additionally, since the side P 5 b -P 6 b of the X 2 and the side P 5 a -P 6 a of the X 3 are located adjacent to each other in an overlapping manner, the intersection point Q 5 b of the X 2 and the intersection point Q 5 a the X 3 are overlapped with each other. Thus, a connecting line L 5 b of the X 2 and a connecting line L 5 a of the X 3 are connected. By connecting the connecting lines as just described, a number of the opening regions by the thin metal wires can be formed, and the thin metal wires 12 are formed in a mesh shape.

Second, the X 1 and X 3 are located opposed to each other via the side P 4 b -P 5 b of the X 2 , and are arranged such that the fourth vertex P 4 a of the X 1 and the fifth vertex P 1 a of the X 2 are located opposed to each other. When P 1 a is on the upper side and P 4 a is on the lower side as the line connecting P 1 a , and P 4 a of the X 1 is defined as the axis, the directions indicated by the virtual arrow d 4 a of the fourth vertex P 4 a of the X 1 and the virtual arrow d 5 a of the fifth vertex P 5 a of the X 3 are both arrows that indicate the right direction. As just described, a number of the opening regions formed by the thin metal wires are aperiodically arranged.

A length A of one side of the virtual pattern Xa is 150 μm to 3000 μm, and is preferably 500 μm to 2000 μm. When the length is 150 μm or more, the thin metal wires 12 can be prevented from being densely formed on the transparent substrate 11 . When the length is 3000 μm or less, the number of thin metal wires 12 is reduced, and the resistance value can be prevented from increasing.

A length B of one side of the hexagon Sa is preferably from A/4 μm to 3A/4 μm. When the length B is in such a range, the hexagon Sa can be prevented from having the area extremely different from that of the graphic formed by the connecting lines and the sides of the hexagon Sa, and a location where the thin metal wires are sparsely disposed and a location where the thin metal wires are closely disposed can be prevented from being formed. Each inner angle θa of the hexagon Sa is preferably 90° or greater. When the inner angle θa is 90° or greater, the thin metal wires are controlled to have the equal width near intersection points of the thin metal wires, and the increase of the width of the thin metal wires near the vertex of the hexagon Sa can be prevented from causing glare.

A length C of each of the connecting lines L 1 a to L 6 a is preferably A/4 μm to A/2 μm. When the length C is in such a range, the hexagon Sa can be prevented from having the area extremely different from that of the graphic formed by the connecting lines and the sides of the hexagon Sa, and a location where the thin metal wires are sparsely disposed and a location where the thin metal wires are closely disposed can be prevented from being formed.

The conductive sheet 10 can be manufactured by a method in which a metal film including a blackened layer is formed on the transparent substrate 11 by sputtering or transferring metal foil to be patterned by etching, or a method in which conductive ink is pattern-printed on the transparent substrate 11 .

As described above, in the conductive sheet 10 according to the first embodiment, the hexagon Sa and the connecting lines L 1 a to L 6 a are formed by the thin metal wires 12 in the virtual pattern Xa, and the vertexes of the hexagon Sa and the first intersection point Q 1 a to the sixth intersection point Qua are respectively connected by the connecting lines L 1 a to L 6 a . Densely laying the virtual patterns Xa or the inverted virtual patterns Xb on the transparent substrate 11 while rotating the virtual patterns Xa or the inverted virtual patterns Xb such that the intersection points disposed on the respective sides of adjacent virtual patterns Xa or the inverted virtual pattern Xb are overlapped with each other and that the opening regions R formed by the plurality of thin metal wires 12 are aperiodically arranged can form the plurality of opening regions R aperiodically arranged by the plurality of thin metal wires 12 and form the plurality of thin metal wires 12 in an irregular mesh shape on the transparent substrate 11 .

Additionally, by setting the length A of one side of the virtual pattern Xa to be 150 μm to 3000 μm, the thin metal wires 12 can be prevented from being densely disposed, or the resistance value can be prevented from being increased by a decreased number of thin metal wires 12 . The length B of one side of the hexagon Sa is A/4≤B≤3A/4, and each of the connecting lines L 1 a to L 6 a connects the vertex of the hexagon Sa and the intersection point located at the shortest distance from the vertex. Thus, the hexagon Sa is disposed near the center of the virtual pattern Xa, and the connecting lines L 1 a to L 6 a are disposed to radially extend from vertexes of the hexagon Sa to respective sides of the virtual pattern Xa. In such a configuration, when the virtual pattern Xa and the inverted virtual pattern Xb are densely laid on the transparent substrate 11 , the thin metal wires 12 are disposed in a non-sparse manner on the transparent substrate 11 , and variations of the area of the opening region R are reduced. As a result, a location where the thin metal wires are sparsely disposed and a location where the thin metal wires are closely disposed can be prevented from being formed, and deterioration in visibility due to glare can be prevented. By setting each inner angle θa of the hexagon Sa to be 90° or more, the increase of the width of the thin metal wires near the vertex of the hexagon Sa can be prevented from causing glare.

Next, a second embodiment of the present disclosure will be described with reference to the drawings.

Second Embodiment

Referring to FIG. 4 A , a touch sensor 100 according to the second embodiment of the present disclosure includes the transparent substrate 11 , a plurality of electrodes 20 A formed on one surface of the transparent substrate 11 , connection portions 30 A each formed on an end portion of the plurality of electrodes 20 A, terminal portions 40 A connected to external wiring lines, and routed wiring lines 50 A each connecting the connection portion 30 A and the terminal portion 40 A. Further, the touch sensor 100 includes a plurality of electrodes 20 B formed on the other surface of the transparent substrate 11 , connection portions 30 B each formed on an end portion of the plurality of electrodes 20 B, terminal portions 40 B connected to the external wiring lines, and routed wiring lines SOB each connecting the connection portion 30 B and the terminal portion 40 B.

The transparent substrate 11 is sectioned into an operation region V 1 and a peripheral region V 2 . The operation region V 1 is a region of the touch sensor 100 in which an input operation by a user is performed, and the peripheral region V 2 is a region that is covered by a frame-shaped decorative layer or the like of a cover base material after assembly. The plurality of electrodes 20 A and dummy portions 21 A are formed in the operation region V 1 on one surface of the transparent substrate 11 , and the connection portions 30 A, the terminal portions 40 A, and the routed wiring lines 50 A are formed in the peripheral region V 2 .

The plurality of electrodes 20 A are formed in the operation region V 1 . The plurality of electrodes 20 A have a band shape, and are arranged on the top surface of the transparent substrate 11 to extend in the y-axis direction and be located side by side in four rows in the x-axis direction. The plurality of electrodes 20 A is made up of the plurality of thin metal wires described in the first embodiment. The plurality of electrodes 20 A form electrodes of the touch sensor.

The size of the plurality of electrodes 20 A is determined by the size of the operation region V 1 and resolution and thus is not limited to particular sizes, and when the length of one side of the virtual pattern Xa described above is A and the width of the electrode 20 A is W, the relationship 3A≤W is preferably satisfied.

The dummy portion 21 A is formed in a region of the operation region V 1 in which the plurality of electrodes 20 A are not formed. The electrodes 20 A and the dummy portions 21 A are alternately arranged. Similarly to the plurality of electrodes 20 A, the dummy portions 21 A are made up of the plurality of thin metal wires described in the first embodiment. Referring to FIG. 4 B , when a region K including the boundary of the electrode 20 A and the dummy portion 21 A in FIG. 4 A is enlarged, the electrode 20 A and the dummy portion 21 A are disconnected by a disconnection portion 22 A so as not to be electrically connected. The disconnection portion 22 A is formed to section the operation region V 1 and form the band shape of the electrode 20 A, and the electrode 20 A and the dummy portion 21 A are separated by the disconnection portion 22 A. The thin metal wire 12 is not formed in the disconnection portion 22 A. The width of the disconnection portion 22 A is preferably 1 to 10 μm. When the width of the disconnection portion 22 A is in such a range, the appearance of the boundary line between the electrode 20 A and the dummy portion 21 A due to the presence or absence of the thin metal wire can be prevented.

The connection portion 30 A serves to connect the electrode 20 A and the routed wiring line 50 A. The thin metal wires 12 forming the electrode 20 A can be collectively connected by the connection portion 30 A to the routed wiring line 50 A. The connection portion 30 A has a rectangular shape and is formed at one end in the longitudinal direction of the electrode 20 A having a hand shape. The connection portions 30 A are formed in the peripheral region V 2 to be partially overlapped with the plurality of thin metal wires 12 forming the plurality of electrodes 20 A. The electrode 20 A extends to the boundary line of the operation region V 1 , and one side of the rectangular shape of the connection portion 30 A is overlapped with the boundary line between the operation region V 1 and the peripheral region V 2 . The width of the connection portion 30 A is equal to the width of the electrode 20 A. Similarly to the thin metal wire 12 , the connection portion 30 A is formed of a layered film of the first blackened layer, the metal layer, and the second blackened layer that are layered in the mentioned order from the transparent substrate 11 side.

The terminal portion 40 A serves to connect the touch sensor 100 to an external wiring line of a flexible wiring substrate or the like, and is formed near an outer edge on the transparent substrate 11 . The routed wiring line 50 A serves to connect the electrode 20 A and the terminal portion 40 A, and the routed wiring lines 50 A are connected to the terminal portions 40 A to be bent in the middle and gathered near the center. Similarly to the thin metal wire 12 , the terminal portion 40 A and the routed wiring line 50 A are each formed of the first blackened layer, the metal layer, and the second blackened layer that are layered in the mentioned order from the transparent substrate 11 side.

The plurality of electrodes 20 B and dummy portions 21 B are formed in the operation region V 1 on the other surface of the transparent substrate 11 , and the connection portions 30 B and the terminal portions 40 B are formed in the peripheral region V 2 . The plurality of electrodes 20 B are disposed on the back surface of the transparent substrate 11 to extend in the x-axis direction and be located side by side in five rows in the y-axis direction. The connection portion 30 B is formed at one end in the longitudinal direction of each of the plurality of electrodes 20 B having a band shape.

The terminal portions 40 A and 40 B formed on the top surface and back surface of the transparent substrate 11 are connected to a flexible printed circuit board (not illustrated). The flexible printed circuit board is connected to a control unit that achieves capacitive touch detection. The control unit detects a current flowing in response to changes in electrostatic capacitance, which occur in the plurality of electrodes 20 A and 20 B when the finger of a user or a conducting body of a stylus or the like is closely located or separated, and thus a touch operation and a touch position by the user can be detected.

A method for manufacturing the touch sensor 100 will be described.

First, a first blackened film layer, a metal film layer, and a second blackened film layer are formed in the mentioned order on the both surfaces of the transparent substrate 11 by sputtering or transferring metal foil. Additionally, a resist layer is formed on the second blackened film layer, and the resist layer is patterned by exposure and developing with a pattern mask. Thereafter, by etching the first blackened film layer, the metal film layer, and the second blackened film layer with the patterned resist layer used as an etching mask, electrodes formed of a plurality of thin metal wires, dummy portions, disconnection portions, connection portions, terminal portions, and routed wiring lines are simultaneously formed on the both surfaces of the transparent substrate 11 .

As described above, in the touch sensor 100 according to the second embodiment, the plurality of electrodes 20 A and 20 B are formed of the plurality of thin metal wires according to the first embodiment, and thus the occurrence of glare due to a difference between a location where the thin metal wires are sparsely disposed and a location where the thin metal wires are closely disposed or glare due to the increase of the width of the thin metal wires near the intersection points at which the thin metal wires intersect one another can be suppressed.

In addition, since the dummy portions are formed in locations in the operation region V 1 in which the plurality of electrodes are not formed, the phenomenon where the shape of the electrode pattern is observed by an operator due to the presence or absence of electrodes can be suppressed, and thus deterioration in visibility can be prevented. Since the dummy portions are formed of the plurality of thin metal wires according to the first embodiment in the same manner as the plurality of electrodes, the occurrence of glare can be suppressed in both the dummy portions and the plurality of electrodes. As a result, the visibility of the operation region V 1 of the touch sensor 100 can be improved. Also, in the method for manufacturing the touch sensor 100 according to the second embodiment, the plurality of electrodes, the dummy portions, the connection portions, the terminal portions, and the routed wiring lines can be simultaneously formed, and thus the manufacturing process can be prevented from being complicated.

Note that in the embodiment described above, the hexagon Sa is formed in the virtual pattern Xa, but Sa may be an n-sided polygon (n≥5), When n=5, that is, Sa is a pentagon, five connecting lines of the connecting lines L 1 a to L 6 a connect the vertexes of the pentagon Sa and the intersection points on the virtual pattern Xa, and the remaining one connecting line connects the side of the pentagon Sa and the remaining intersection point on the virtual pattern Xa. The length C of each of the connecting lines L 1 a to L 6 a is preferably in the range A/4≤C≤A/2. When n≥7, that is, Sa is a polygon that is a heptagon or more, the connecting lines L 1 a to L 6 a may connect the vertexes of the polygon Sa and the intersection points on the virtual pattern Xa, which are located at the shortest distance from the vertexes. Additionally, the length C of each of the connecting lines L 1 a to L 6 a may be in the range A/4≤C≤A/2.

In the embodiment described above, the virtual pattern Xa and the inverted virtual pattern Xb that are rotated clockwise are used and densely laid; however, the virtual pattern Xa and the inverted virtual pattern Xb may be rotated counterclockwise and used.

In the embodiment described above, the opening region is formed only by the polygon and the connecting lines that are formed in the virtual pattern Xa and the inverted virtual pattern Xb, and thus the thin metal wires 12 are formed in a mesh shape; however, the thin metal wires 12 may be further added. In this case, the thin metal wires 12 are disposed such that the added thin metal wires 12 are not periodically arranged.

In the embodiment described above, the thin metal wire 12 is formed of the first blackened layer, the metal layer, and the second blackened layer that are layered in the mentioned order; however, the layered configuration of the thin metal wire is not limited thereto. For example, the thin metal wire may include only a metal layer, may include a metal layer and a blackened layer that are layered in this order from the transparent substrate side, or may include a blackened layer formed to cover the upper surface and side surfaces of a metal layer formed on the transparent substrate. In addition, the periphery of a metal layer may be completely covered by a blackened layer. In such a configuration, glare when the touch sensor is assembled can be further suppressed.

In the embodiment described above, the plurality of thin metal wires are formed on one surface of the transparent substrate of the conductive sheet; however, the thin metal wires may be formed on the both surfaces of the transparent substrate. In this case, when blackened layers are formed on at least the upper and lower surfaces of a metal layer, visibility can be further improved.

In the embodiment described above, the plurality of electrodes 20 A and 20 B have a belt shape; however, the shape of the electrode is not limited thereto. Another shape of the electrode can be, for example, a shape in which rhombuses are continuously disposed or a comb teeth shape. Also, the number of electrodes, the position of the routed wiring lines, and the position of the terminal portions are not particularly limited.

In the embodiment described above, the dummy portion is formed of the thin metal wires according to the first embodiment; however, the thin metal wire pattern of the dummy portion is not limited thereto. The dummy portion may be formed of a thin metal wire pattern that can suppress the occurrence of glare.

In the embodiment described above, the electrodes are formed on the both surfaces of the transparent substrate 11 of the touch sensor 100 ; however, the configuration of the touch sensor is not limited thereto. Two transparent substrates each having electrodes formed on one surface thereof may be attached such that the other surfaces of the transparent substrates are located opposed to each other or that the other surface of the transparent substrate may be adhered in an overlapping manner to the electrodes via an adhesive thereon.

In the embodiment described above, the connection portion is formed at one end of the electrode; however, the connection portions may be formed at both ends in the longitudinal direction of the electrode. For example, the connection portion 30 B is formed at the left end portion of the electrode 20 B, and in the meantime, the connection portion 30 B may be further formed at the right end portion of the electrode 20 B. In this case, the terminal portions 40 B are also formed on the right side of the terminal portions 40 A, and the routed wiring lines 50 B are connected to the respective terminal portions 40 B. The position of the terminal portions and the arrangement of the routed wiring lines are not limited to particular positions.

In the embodiment described above, the plurality of electrodes, the dummy portions, the connection portions, the terminal portions, and the routed wiring lines are simultaneously formed; however, the method for manufacturing the touch sensor 100 is not limited thereto. For example, the thin metal wires according to the first embodiment are formed in the operation region V 1 ; thereafter, the disconnection portions are formed by cutting the thin metal wires with a laser, and the plurality of electrodes and the dummy portions may be formed. Further, the plurality of electrodes and the dummy portions are formed in the operation region V 1 ; thereafter, the connection portions, the terminal portions, and the routed wiring lines may be formed in the peripheral region V 2 . Furthermore, instead of simultaneously forming the portions on the both surfaces of the transparent substrate 11 , the portions may be separately formed on each one of the surfaces.